Apparatus for casting dental plates in metal



ec. 4 W23 H. l... HODAY ET AL APPARATUS FOR CASTING DENTAL PLATES IN METAL Filed May 9, 192

' Patented Dec. 4, 19 23.

UNITED STATES PATENT OFFICE.

' mnnm'r LESLIE 303ml! AND FREDERICK WILLIAM NUNN, or MELBOURNE,

VICTORIA, AUSTRALIA.

APPARATUS FOR CASTING DENTAL PLATES IN METAL.

Application filed May 9,

To all whom it may concern:

Be it known that HERBERT LESLIE HOB- DAY and FREDERICK WILLIAM NUNN, subjects of the King of Great Britain, residing at 9 Collins Street, Melbourne, in the Statev of Victoria, Commonwealth of Australia,

According to our invention, a wax plate is made from the impression taken from the patient and isinvested in a cylinder or pot in the usual way. After burning out the wax, gold or other metal to form the plate is reduced to a molten condition on the top ofthe cylinder or pot and over the sprue or channel between the metal and the mould. The pot is held upon the end of a rigid rod secured to and depending from a rotatable horizontal spindle and upon the pot being swung around with the rotating spindle several tlmes at a fair rate of speed, the molten metal will be forced into the mould to form the plate. It is important to rigidly secure the bar to the spindle to insure that the investment shall truly rotate in a circle terweighted, and the rotatable spindle can be actuated through a sprocket and chain riving means.

The investment pot can be formed of metal or of a refractory material'and is perforat- .ed in the sides. roay be fitted with a socket member which in tutti, can be provided with liners to acgearing orother suitable and convenient It is held in a basket that 1922. Serial No. 559,542.

comlnodate various sized investment pots. Means are provided for the ingress and egress of the pot from the basket.

But in order to fully understand our said invention, reference is made to the accompanying drawings, in which- Figure 1 is a perspective view of the machine. Q

Figure 2 a detail sectional plan view of the basket and fittings for holding'the investment, and 4 v Figure 3 is a sectional elevation of the same.

Between the stout cheeks of, the machine the horizontal spindle 3 is mounted andwhich can be driven through the usual sprocket and chain gearing 4. Depending from the spindle 3, to which it is securely attached, is a stout rod 5 upon the lower end of which the investment cylinder basket 6'is hung. This basket is conveniently construct-- ed of. two metal straps placed at right angles,. the one to the other, and is brazed to the rod 5. To the lower extremities of the basket 6 a ring 7 is riveted, the ring being provided with bayonet joints. Fitting easily within this ring is a socket plate 9 into which fits a hollow flanged plate 10. In the hollow or central partof this plate an investment ipot 11 of comparatively small diameter, such as might be employed; in the investment of smaller work, is vertically held (as shown in Fig. 2), while on the outside of the flange a larger investment cylinder 11 can belaccommodated (as in Figs. 2 and 3). A still larger cylinder, such as would be used in the large -work, can be inserted and held within and against the turned up, edge of the socket p ate 9, on which are pins 12 adapted to fit the bayonet joint in the ring. Thus, by

means of the parts described, investment pots 1 of' various diameters can be satisfactorily held in the basket. To insert or remove'the same from the basket, the pins 12 are moved in the joints and the socket plate 9 withdrawn together with the su ported parts.

The pots or cylinders hol ingthe investment are perforated in the sides to facili- .tate the same heating quickly and evenly when placed over a burner to reduce the wax late. p The rod 5 is provided upon the opposite side of the spindle 3 with a counter-weight 8 which assists in the smooth working of the machine when the basket is g.

lln the case of very small Work, such as ring secured to the lower part of the basket the casting of inlays, the plate 10 can be sides, beyonet joints in the ring, a socket made with a smaller central opening, there plate arranged in and (letachably connected being two or more such plates for selection to the ring and a hollow flanged member 15 5 for use in the socket member 9. fitting Witlun the socket plate and arranged Having now described our invention what to accommodate investment pots of varying We claim as new and desire to secure by Letdiameters.

ters Patent is in testimony whereof we afiix our signe- In a machine for casting dental plates a tures. to basket on the end of a rigid rocl secured to HERBERT LESLIE HQBDAY.

sm& clepending from e rotateble spindle, a, FREDERICK WILLIAM NUNN. 

